<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        ul li:first-child {
            background-color: pink;
        }
        
        ul li:last-child {
            background-color: deeppink;
        }
        /* nth-child(n)  我们要第几个，n就是几  比如我们选第8个， 我们直接写 8就可以了 */
        
        ul li:nth-child(8) {
            background-color: lightpink;
        }
    </style>
</head>

<body>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
        <li>6</li>
        <li>7</li>
        <li>8</li>
        <li>9</li>
        <li>10</li>
    </ul>
</body>

</html>